The present invention relates to liquid and lyophilized viral vaccines. More particularly it relates to a stabilizer for liquid and lyophilized viral vaccines.
Due to the worldwide distribution of vaccines and the diversity of ambient temperatures, there has been a need to stabilize these preparations for transportation and use. Several stabilization methods have been used in the past.
(A) Low temperatures (-10.degree. C. to -70.degree. C.). The need for low temperature storage facilities which are not always available limits the practicality of this approach.
(B) Lyophilization Although lyophilization suffers the disadvantages of being an expensive procedure, lyophilized vaccines are reasonably stable and are stored at 4.degree.-8.degree. C. until needed. During this storage period, however, the vaccines slowly deteriorates until after about 12-24 months it does not have sufficient titer to confer immunization. Furthermore, since the lyophilized vaccine must be reconstituted prior to use, the liquid reconstituted preparation loses potency while standing at room temperature. This can result in insufficient titer to confer immunity and results in failure of immunization program.
(C) Stabilizers These are chemical compounds added to the vaccine and are used in conjunction with either lower temperature storage or lyophilization methods. While chemical stabilizers, e.g., MgSO.sub.4, SPGA (a stabilizer described by Bovarnick et al., J. Bact. 59:509-522 (1950), the disclosure of which is incorporated herein by reference) and the like are described in the prior art, none imparts the desired enhanced sustained level of stability. The mixture contained 0.218 M sucrose, 0.0038 M monopotassium phosphate, 0.0072 M dipotassium phosphate, 0.0049 M monosodium glutamate, and 1% bovine albumin powder) and the like are described in the prior art, none imparts the desired enhanced sustained level of stability.